/*
 * Copyright 2017-2024 John A. De Goes and the ZIO Contributors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package zio

import zio.internal.NamedThreadFactory
import zio.stacktracer.TracingImplicits.disableAutoTrace

import java.util.concurrent._

private[zio] trait ClockPlatformSpecific {
  import Scheduler.CancelToken

  private[zio] val globalScheduler = new Scheduler {

    private[this] val service = makeService()

    private[this] val ConstFalse = () => false

    private final val MaxMillis = Long.MaxValue / 1000000L

    def asScheduledExecutorService: ScheduledExecutorService =
      service

    def schedule(task: Runnable, duration: Duration)(implicit unsafe: Unsafe): CancelToken =
      (duration: @unchecked) match {
        case Duration.Infinity => ConstFalse
        case d if d.isZero || d.isNegative =>
          task.run()
          ConstFalse
        case d =>
          val millis = d.toMillis
          val future =
            if (millis < MaxMillis)
              service.schedule(
                task,
                d.toNanos,
                TimeUnit.NANOSECONDS
              )
            else
              service.schedule(
                task,
                millis,
                TimeUnit.MILLISECONDS
              )

          () => future.cancel(true)
      }
  }

  private[this] def makeService(): ScheduledExecutorService = {
    val service = new ScheduledThreadPoolExecutor(1, new NamedThreadFactory("zio-timer", true))
    service.setRemoveOnCancelPolicy(true)
    service
  }
}
